Caption: Vitamin K2, molecular model. The chemical formula for vitamin K2, also called menaquinone, is C31.H40.O2. Atoms are represented as balls and are colour-coded: carbon (blue), hydrogen (gold) and oxygen (red). While vitamin K1 is found in dark green leafy vegetables, meat, dairy products and eggs, vitamin K2 is found only in bacteria and foods made from fermented soya beans. Vitamin K is necessary for blood clotting and bone growth. Deficiency can lead to uncontrolled internal bleeding, and mineral deposits on cartilage regions and on the inner walls of blood vessels.